Influence of PEG generated osmotic stress on shoot regeneration and some biochemical parameters in Lathyrus culture

Abstract

Several Lathyrus species and in particular Lathyrus sativus (grass pea) display much tolerance to drought and have great agronomic potential as grain and forage legumes. Studies on these crop species could improve our understanding of the mechanisms of plant resistance to water stress. This investigation was aimed at examining the effect of low water potential generated by polyethylene glycol (PEG) 6000 on seed germination, shoot regeneration and some biochemical parameters related to drought stress. Seeds of eight Lathyrus accessions (six of L. sativus, one of L. cicera, one of L. tingitanus) were cultured on MB (MS macro and microelements with B5 vitamins) medium with addition of 5 mg/l BAP (6-benzyloaminopurine). Different levels of water-stress were induced by using three concentrations of PEG 6000 (50, 100 and 150 g/l) in MB medium. Osmotic stress had no influence on seed germination of any of the accessions tested. However, an increased concentration of PEG in the media caused a decrease in the multiplication rate and vigour of newly regenerated shoots. The percentage content of dry matter and proline content in Lathyrus shoots increased significantly under osmotic stress. In turn, water stress had a little effect on photosynthetic pigments.